The present invention relates to a gas spring, and more particularly to a gas spring having a multiple of auxiliary volumes located about a central piston cylinder.
Pneumatic or gas springs are utilized in various commercial articles including the automotive industry. Gas springs are also utilized in many other fields to provide a counterbalance force for closure units, such as lids, doors, and cabinets, and amongst others where the gas springs operate as replacements for mechanical spring type fittings. In some fields of use, such as automotive, the change of the surrounding temperature can be quite substantial.
When the temperature drops, the pressure of the gas within the spring unit drops and concurrently therewith the force holding the piston rod extended or in the hold-open position often drops below that required to hold the closure member in an open position. Conversely, at higher temperatures the force is often too high which may make the closing member difficult to move. To counter these disadvantages, the industry has evidenced a desire to have pneumatic springs which in some manner will have their output force compensated for temperature changes.
One known temperature compensation gas spring utilizes two chambers within the gas spring body in which the piston reciprocates. The chambers are defined along an axis of reciprocation of the gas spring. Between the two chambers form a working chamber where the piston reciprocates and a storage chamber that is divided by a temperature responsive valve. When the temperature rises past a predetermined value, the valve is closed and the working volume is reduced.
Although effective, the known temperature compensation gas springs must be of an increased length to provide space for both chambers and temperature responsive valves and provides compensation in one single step. Disadvantageously, the additional length may preclude usage in many applications.
Accordingly, it is desirable to provide a temperature compensation gas spring which is effective yet compact in length and allows for compensation to occur in multiple steps.